Weight checking sampler



P 19, 1950 G. o. ALVORD 2,523,179

WEIGHT CHECKING SAIIPLER Filed Jan. 3, 1947 I N VEN TOR. R 0 A L vowPatented Sept. 19, 1950 2,523,179 WEIGHT CHECKING SAMPLER Grove D.Alvord, Indiana, Pa., assignor to Syntron Company, Homer City, Pa., acorporation of Delaware Application January 3, 1947, Serial No. 720,044

3 Claims.

This invention relates generally to the control of continuously flowingmaterials and more particularly to apparatus for checking the amount byweight of a continuously flowing material by extracting and measuring asample of the material being supplied with minimum disturbance to thefeed.

The principal object of this invention is the provision of apparatus forextracting a sample and weighing the same for the purpose of checkingthe delivery of continuously flowing material.

Another object is the provision of apparatus for checking the deliveryof a gravimetric feeder after the material or its delivery rate has beenchanged.

Another object is the provision of apparatus for removing a sample froma continuous flow of a poisonous or obnoxious material to check the rateof delivery of a gravimetric feeder without manually handling the same.

Another object is the provision for automatically removing a sample froma volumetric feeder to check its rate of continuous flow.

Another object is the provision for automatically removing a sample froma continuous flow of material to check the rate of flow and return thechecked sample to the normal course of the material.

Another object is the provision of apparatus for determining the rate offlow factor of a continuous gravimetric feeder and for periodicallychecking this factor.

Other objects and advantages appear hereinafter in the followingdescription and claims.

A practical embodiment illustrating the principles of this inventions isshown in the accompanying drawing wherein:

Fig. l is a view in elevation of a gravimetric feeder in a weightsampler comprising this invention.

Fig. 2 is a diagrammatic view illustrating a snap-acting flap valveemployed to direct material to the sampler.

lustrated at l2 and is arranged to drive the end less conveyor belt I lat a uniform speed.

The material to be measured and fed is re-- ceived by chute 13 from abin or other supply which directs the material to the hopper I4suspended by the slings l5 attached to the frame? 16 which is adjacentand secured to theframe l..

A flexible dust hood I? is arranged to encircle the chute l3 and the topof the hopper M for' the purpose of preventing material or the dustcreated thereby from escaping as it is trans-- ferred from the chute tothe hopper. The hopper H in turn is provided with a flexible dust hood18 which is connected at its lower end to the enclosed conveyor trough20. The conveyortrough 20 is provided with an enlarged receiving end 2ihaving a sloping bottom 22 and a tubular Referring to the drawings, thegravimetric feeder is enclosed in the base frame I which is arranged tosupport the platform scale 2 having a beam arm 3 and the dial scale 4.The beam 3 is arranged to carry the usual counterpoise 5 and 6 tocorrect the tare weight and is also arranged to actuate switch I and thetransmitter 8 for controlling the supply to the gravimetric feeder. Thescale platform 9 is arranged to support the hanger structure ID on whichis suspended the synchronous conveyor belt mechanism ll. This conveyoris operated by a synchronous motor i1- trough section 23 which isarranged to deliver the material directly on the center of the syn--chronous conveyor belt I l. The conveyor trough 20 is also provided witha pair of wing plates 2 which are welded to the trough and are securedby the bolts 25 to the armature supporting member 26 of the vibratorymotor 21. The armaturesupporting member 25 is in turn bolted to theintermediate section of the leaf springs 28, the: ends of which areclamped in the slots 29 of the: frame 30 by the clamping bars 3|. Avibratory motor of this character is disclosed in United. States LettersPatent 2,356,961 and does not per se form a part of this invention. Themotor Zl: and the trough 20 are supported by the coil springs 32 and 33.The weight of the conveyor trough 20 is materially less than the weightof the motor structure 21 to prevent the latter from absorbing any ofthe vibratory action delivered to the former. I

A control motor 34 is mounted on the frame I and is arranged to operatethe crank arm 35 to which one end of the bifurcated pit man 36 ispivotally attached. The other ends of the pitman. are pivotally attachedat to the g-udgeons on the opposite sides of the hopper I 1. Owing tothe fact that the hopper is supported in the slings l5 it is permittedto be swung back and forth by means of the crank 35 operating throughthe pitman 3B. The discharge mouth 38 of the hopper it has the sameslope as the bottom 22 of the conveyor trough 2D and when the crank 35swings the hopper M to its extreme position to the the mouth 38 isclosely adjacent the sloping floor 2.2 thereby acting as a valve toprevent the flow of material from the hopper H. to the conveyor trough20. How- 3 enough to engage the floor 22 6f the conveyor trough when thelatter is being vibrated but it is sufiiciently close to prevent theflow of the material from the hopper to the trough.

A vibrator 40 is attached to the side of the hopper and is arranged tovibrate the material in the hopper and maintain a uniform flowtherefrom.

The discharge end of the synchronous conveyor belt II is arranged todeposit the material into the chute 4|. This chute is provided with a Yconnection having a snap-acting flap valve 42 which is shown in Fig. 1in the position to direct the material down the chute 43 to a bin orcontainer into which the measured material is delivered for use. If thevalve 42 is operated to move it in the position shown in Fig. 2 thematerial is deflected into the chute 44 where it is deposited into thehopper 45. The dust hood 46 is arranged to connect the hopper 45 to thechute 44 to prevent the escape of any dust therefrom. The hopper 45 isin turn supported on the weighing platform 41 of the scale 48. Thehopper 45 is provided with a gate member 50 which when opened permitsthe material in the hopper 45 to be discharged back into the chute 43. Aflexible hood connection is made between the mouth of the hopper and thechute 43 to prevent the escape of material or dust from this connection.

52 is a vibrator attached to the hopper 45 for vibrating the material toprovide uniform flow thereof when the gate 50 is opened. This vibratorfunctions to completely discharge the hopper 45 and thus prevent falseindication upon checking the next sample taken from the feeder. Thescale 48 may be of a graphic type which will record the weight of eachsample taken from the delivery of the gravimetric feeder. After thereading has been taken or recorded from the scale 48 the gate 50 may beopened to discharge the material from the hopper 45 to the chute 43.

As shown in Fig. 2, the flap valve 42 may be secured to the shaft 53journaled in the Y connection of the chutes 43 and 44 and extendingthrough one wall and has the valve arm 54 fixed thereto. A manualoperating lever 55 is journaled on the shaft 53 and is provided with alug 56 arranged to hold one end of the coil spring 51, the other endbeing attached to the lug 58 on the valve arm 54. Thus when theoperating lever 55 is swung to a position beyond the plane of the valve42 and its valve arm 54, the spring 5'! will cause the latter to snap tothe opposite position. A valve of this character provides a uniformspeed of the movement of the valve which materially aids in obtainingconsistent results in checking the output weight of the gravimetricfeeder by sample.

The chute 4| of the weight checking sampler shown in Fig. 2 may besupplied directly from the chute |3 when disposed vertically or from theconveyor 26. In either event the apparatus supplying the material isprovided with a controller such as the resistor 59 which when adjustedto different positions regulates the rate of fiow of material from thetrough 20. When employed with a gravimetric feeder as shown in Fig. 1,the transmitter 8 is arranged to vary the rheostat 59 to speed up orslow down the operation of the vibratory conveyor to automaticallymaintain a constant load on the conveyor belt II as shown and describedin Patent 2,429,864.

To provide an automatic weight checking sampler the manual operatinglever is equipped with the gear segment arranged to mesh with the pinion6| of the reversible servomotor 62. This servomotor may be energized bythe push button timer 63 arranged when started by the push button 64 toclose a holding circuit through the switch 65 that maintains the timerenergized until after it has functioned to operate a completed cycle.

As shown in Fig. 2, the valve 42 is set to direct the material from anydesired feeder or supply source, such as the vibratory feeder 20 or thegravimetric feeder shown in Fig. 1, to the chute 43. Upon depressing thepush button 64 current flows from the source of electrical currentsupply 66 through the line 61, the push button 64, the line 68, thetimer motor 69, and returns through the line to the other side of theelectric current supply II. The timer motor first closes the switch 65to establish the holding circuit from line 61 to line 68 to maintain thetimer motor 69 energized for the complete cycle. The timer motor thenfunctions to close the switch 12 to complete a circuit through theservomotor 62, current flowing from line 6'! through the servomotor 62,and return through line 13, switch 12, line 10 to the return currentsupply The servomotor is thus energized to swing the lever 55 to theright to throw the valve 42 in the same direction and direct the flow ofmaterial to the chute 44.

After a predetermined length of time, the timer motor 69 moves theswitch 12 to connect the line 14 with the line 10 to reverse theservomotor 62 causing the valve to assume the position shown in Fig. 2and redirect the flow of material to the chute 44. The sample ofmaterial has thus been taken from the stream and the material is againdirected through the chute 43.

After the sample has been weighed or its Weight recorded the valve 5|]is operated to slowly meter the material from the hopper 45 to the chute43 to prevent the sample from unduly swelling the stream of material.The valve 50 may also be operated by a servomotor 15 and bothservomotors 62 and 15 are provided with check circuit switches thatprevent the operation of one until the oper ation of the other has beencompleted.

The sample of material being withdrawn for a predetermined period oftime thus provides an actual recording of the flow of material per unitof time which is employed to establish a flow factor for the materialpassing through the chute 43 regardless of whether it comes from thechute l3 when disposed vertically, the feeder 20 or the conveyor I ofthe gravimetric feeder as shown in Fig. 1. The sample weighed in thehopper 45 provides the weight of material per unit of time. When thisweight is divided by the time required in taking the sample and thesetting of the controller feeding, the chute 4| provides a calibration,which is the flow factor employed for regulating the setting of theconveyor controller to determine the desired amount of materialcontinuously discharged to the chute 43. The factor thus obtained,multiplied by the scale reading 4 provides the weight of material fed bythe gravimetric feeder per unit of time.

If it is desired to change the rate of flow of material fed by thegravimetric feeder the rate indicator controller 16 is adjusted by therate setting knob 71 to a position, the value of which is obtained bydividing the weight of the sample times the desired rate of flow by thetime required to take the sample and the setting of the control 16 whenthe sample was taken. The control may then be reset to this new positionto cause the feeder to supply the material at the new desired rate. Therate indicating controller 16 is also disclosed in Patent 2,429,864.

If the vibratory feeder 20 is supplying the chute 4| directly, thefactor of the rate of flow of material is determined by dividing theweight of the sample by the time required to take it and the setting ofthe control rheostat 59. The sample provides the weight of material perunit of time. When it is desired to change the rate of flow the desiredrate of feed times the weight of the sample divided by the setting ofthe control 59 and time for taking the sample, provides the adjustmentof the controller 59 in terms of its setting to provide the new rate offlow.

Upon installing, cleaning, or changing the rate of flow of gravimetricfeeders of this character, it is preferable to establish a flow factorby which the dial or scale setting is multiplied to provide the weightper unit of time of the flow of material. This factor may change with achange in the character or grade of material, a change in the tareweight of the feeder when cleaned, or other factors contributing to theoperation of the machine. Any large change in the rate of flow of somematerials may not produce a straight line function of the machine whichwould necessitate a check of the flow of material.

I claim:

1. Apparatus for checking the delivery of the continuous flowinggranular material from a feeder supplying a stream of granular materialat a substantially uniform rate, comprising a chute mounted to receivethe whole of the stream of granular material from the feeder and havinga Y-connection to provide alternate branches extending therefrom, abiased valve mounted in said Y-connection to control the flow of thestream of the granular material to a selected branch, a hopper connectedto receive the whole of the stream from one of said branches andsupported on a weighing machine, and a control discharge valve on saidhopper constructed to return the granular material at a selected rate offlow from the hopper to said other branch.

2, Apparatus for checking delivery of continuous flowing granularmaterial from a feeder supplying a stream of granular material at asubstantially uniform rate, comprising a chute mounted to receive thewhole of the stream of granular material from the feeder and having aY-connection to provide alternate branches extending therefrom, a biasedvalve mounted in the Y-connection to control the flow of the stream ofgranular material to a selected branch, a hopper connected to receivethe whole of the stream from one of said branches and supported on aweighing machine, independent motor means to fiop said valve and divertthe whole of the stream to the branch directed to said hopper for agiven length of time to check the rate of flow of material delivered bythe feeder, and valve means to return the granular material from thhopper to said other branch.

- 3. Apparatus for checking the delivery of the continuous flowinggranular material from a feeder supplyin a stream of granular materialat a substantially uniform rate, comprising a chute mounted to receivethe whole of the stream of granular material from the feeder andhavingalternate branches extending therefrom, a biased valve mounted tocontrol the flow of the stream of the granular material to a selectedbranch, a hopper connected to receive the whole of the stream from oneof said branches and supported on a weighing machine, and a controldischarge valve on said hopper constructed to return the granularmaterial at a selected rate of flow from the hopper to said otherbranch.

GROVE D. ALVORD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,777,670 Hausman Oct. 7, 19301,996,189 Biro Apr. 2, 1935 2,238,758 Thornhill Apr. 15, 1941 2,327,367Nowak, Jr Aug. 24, 1943 FOREIGN PATENTS Number Country Date 489,555Germany July 28, 1938

